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A
POWER
SUPPLY.
PROVlOE
o,SCONNECT
MEANS
AND
OVERLOAD
PRO.
TECTION
AS REOUIREO.
&;
L.lI(
OR
La,*9
"SE0
AS "10"
LIMIT.
13
1
L6,m
OR ~6,119 "SE0
AS Low L,M,T,CIRC"LATOR
CONTROLLER.
,*.oze
FIG. O-HIGH
LIMIT AND LOW LIMITKIRCULATO~
APPLICATION
IN AN OIL-FIRED
HYDRONIC
SYSTEM WITH DOMESTIC HOT WATER.
-LINE
VOLTAGE
CONTROL
-
LOW VOLTAGE
PROVlDE
CNSCONNECT MEANS AND OVERLOAD
PROTECTION
AS
REQVIRED.
,,.on
FIG. lo--HIGH
LIMIT
AND SEPARATE
LOW LIMIT
AND
CIRCULATOR
APPLICATION
IN AN
OIL-FIRED
HYDRONIC
SYSTEM WITH DO-
MESTIC HOT WATER.
OPERATION
As the liquid filling the sensing bulb and capillary
expands
and contracts,
it moves
a diaphragm.
Move-
ment of the diaphragm
is transferred
by a lever to the
snap-acting
switch in the controller.
HIGH OR LOW LIMIT ACTION
(L4188, L4189)
The normally
closed
C-l
contacts
open on temper-
ature
rise to the set point,
shutting
off power
to the
controlled
circuit.
On auto recycle
models,
the switch
closes C-l after the temperature
falls past the set point
and through
the differential.
See Fig. 11.
LOW LIMIT/CIRCULATOR
ACTION
(L6188, L6189)
The low limit is connected
to the normally
closed C-l
contacts,
and the circulator
to the normally
open C-2
contacts.
As long as the temperature
at the sensing
bulb is above
set point. the circulator
runs. If sensing
bulb temperature
falls past the set point and through
the differential,
the switch
breaks
C-2 to turn off the
circulator,
and makes C-l to turn on the burner. When
the temperature
rises to the set point, C-2 makes to turn
on the circulator,
and C-l breaks to turn off the burner.
7
On manual
reset
models,
the
reset
button
must
be
pushed before contacts
C-l will close. See Fig. 11.
TEMPERATURE
SETTlNG
SCALE
L4188.9
HIGH OR LOW
LS181.9
LOW LIMIT,
ClRCVLATOR
G. ll-AQUASTAT
CONTROLLER
SWITCH
ACTIO'
ON TEMPERATURE
CHANGE.
66-0061
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